Meantime is normally a noun and needs a preposition in front of it: <em>in the meantime, help yourself to coffee</em>. Meanwhile is an adverb that stands on its own, usually at the start of a sentence: <em>Meanwhile, the kitchen was quietly falling apart</em>. Both refer to the same interval of time — only their grammar differs.
The core difference
Both words describe the stretch of time between one event and another. The difference is what shape they take in a sentence. Meantime behaves like a noun; meanwhile behaves like an adverb. Get the grammar right and the meaning takes care of itself.
Using meantime
You will almost always see it inside the fixed phrase in the meantime, occasionally for the meantime:
- The report is due on Friday; in the meantime, keep gathering figures.
- Repairs start next month. For the meantime, use the side entrance.
Using meanwhile
It links two things happening in parallel, or moves the reader from one thread of a story to another:
- He was still arguing with the traffic warden. Meanwhile, the meeting had started without him.
- Sales rose in Europe; meanwhile, the American figures kept sliding.
The test
Ask whether the word has "in the" in front of it. If it does, write meantime. If the word is standing alone at the head of a clause with a comma after it, write meanwhile. Put another way: you can say in the meantime or meanwhile, but rarely in the meanwhile and never a bare Meantime, the guests arrived in careful modern prose.
Being honest about the overlap
Both words have historically crossed over, and dictionaries record both uses. In the meanwhile is old and perfectly grammatical — it simply sounds dated now. A bare adverbial meantime (Meantime, nobody had told the client) still appears in journalism, particularly headlines and broadcast scripts, where it reads as a stylistic tic rather than an error. Neither is a mistake you need to correct in someone else's writing; both are choices a careful writer usually avoids because the standard pairing is smoother.
The mistake worth avoiding
Do not use meanwhile as a general-purpose contrast word where however or by contrast is meant. Meanwhile carries a genuine sense of simultaneity. The scheme is popular. Meanwhile, it is expensive jars, because the two facts are not two things happening at once — write however there instead.
And keep meantime as one word. Mean time as two words means something else entirely: an average of time, as in Greenwich Mean Time.
Frequently Asked Questions
Is "in the meanwhile" wrong?
Not wrong, just old-fashioned. It appears throughout older literature and dictionaries still list it. Modern writing overwhelmingly prefers "in the meantime" or a plain "meanwhile".
Can I start a sentence with Meanwhile?
Yes, and it is the most natural position: "Meanwhile, the results were still being counted." Follow it with a comma. Starting a sentence with a bare "Meantime" is far rarer outside journalism.
Is it meantime or mean time?
One word for the interval of time: in the meantime. Two words only in the technical sense of averaged time, as in Greenwich Mean Time.